“You cannot step in the same river twice.”
Heraclitus of Ephesus, also known as the Weeping Philosopher and Heraclitus the Obscure, has left us only a few philosophical sentences. Due to this lack of original writing, Heraclitus’ philosophy remains hard to characterize. His belief seems to have been that the universe is in a constant state of flux, as this famous quote indicates. By the time that you attempt to step into the river a second time, the waters of the river will have moved on and so, the river will not be the same one you stepped into the first time. The sentence also has a second meaning; you cannot step into the same river again because you are no longer the same as the person who took the first step. The question of how identity is preserved over time is one which still animates philosophers today.
“Death need not concern us because when we exist death does not, and when death exists we do not.”
Epicurus and Epicureanism has suffered for many years from a misapprehension about what his philosophy teaches. Epicureanism is a hedonistic philosophy in that it teaches that pleasure is to be sought, but only to the extent that pleasure is the freedom from pain and fear. Epicurus also taught on the gods and death. Epicurus is famous today for his questions regarding the problem of evil existing if there are gods and for this statement about death. Because of death, being dead rather than dying, involves no pain, for Epicurus the state of death is a good thing (or at least not to be feared). Epicurus is well beloved of atheists and humanists today because of his rational outlook. In the Roman period, tombs of Epicureans would have this carved on their tombs- I was not. I was. I am not. I do not care.
“The man is the measure of all things.”
This is the most famous saying of Protagoras, though it is in fact, only the first portion of his statement. The full line runs ‘Man is the measure of all things; of things that are that they are, and of things that are not that they are not.’ Protagoras’ relativism is one of the most extreme ever argued. This means that truth is relative and for each individual truth is different. This can be true with things like temperature – you might find the evening chilly, but for me it is warm. However, we can all agree on the absolute temperature in degrees. Protagoras would disagree and would say that all of our knowledge is sense based and therefore unique to each individual. The problem with relativism is that it makes philosophical discussion impossible; what you think you say and what I hear might be completely different, if we are unable to agree on the objective truth.
“The man is born free and is everywhere in chains.”
The concept of the social contract did not originate with Rousseau, but he was the great popularizer of the concept so neatly summed up in this aphorism. Hobbes thought that in the state of nature, man’s life was one of terrible beastliness (nasty, brutish and short). The social contract is the giving up of these natural freedoms by an individual to better accomplish his goals by working within society. Since man is born free, the chains we wear are ones we choose to wear. It is for the individual to decide which freedoms are worth giving up.
“The unexamined life is not worth living.”
For me this statement of Socrates’, as told by Plato, is sufficient to explain the necessity of studying philosophy. Everyone is pitched into the world blindly and makes do as best they can with the things they are given. For many, this muddling through is hard enough, and examining their motives and the rightness of their actions is just an added, and superfluous, difficulty. However, if we do not examine our lives and use the wisdom we gain from it to plan the future, we are no better than animals following instinct to survive. To take control of your life you must engage your mind. This is not to say that everyone must become a new Socrates, or study academic philosophy, but to paraphrase Voltaire ‘we must all cultivate our own wisdom.’
“I think therefore I am.”
Je pense donc je suis. Cogito ergo sum. These are the words which Descartes used to slay total nihilism. Nihilism is the philosophical denial of existence, either of anything at all or more specific portions of existence. Everyone, at some point in their philosophical musings, wonders whether anything at all exists. Descartes was clever enough to see that pondering, doubting, existence was sufficient to prove that at least one thing exists; the thinker. This has given philosophy something to build on as we can now be certain that one thing exists. There have been criticisms of Descartes argument as a tautology (I think therefore I am) but the basic principle stands as a buttress against the void of nihilism.
“Do unto others as you would have them do unto you.”
This is called the Golden Rule of ethics and has been stated by many people in many places at many times, and so no one religion or philosophy can lay claim to it. This maxim deserves the top spot on any philosophical one-liner list because it so neatly sums up a system of ethics by which many people live their lives. The statement is a challenge as well as an instruction – we must try to empathize with others to understand how we ourselves would wish to be treated if in the other person’s place. There may be exceptions to the rule and it may not be sufficient to a complete moral doctrine, but as a simple rule for daily life it is hard to think of something which would so improve everyone’s lives if put universally into effect.